故事发生在二战期间,在瑞士科学家图贝尔博士发明了一种炸弹装置。福尔摩斯非常有技巧的把他从盖世太保眼皮底下救出来回到伦敦,可图贝尔博士又落到了莫利亚蒂教授的手中。图贝尔画了一张暗号图,福尔摩斯经过努力终于把那些跳舞小人的信号图解开了,并冒险闯入了虎穴。Working for the British government, Sherlock Holmes manages to spirit Dr. Franz Tobel out of Switzerland and into England before the GESTAPO are able to get to him. Tobel has devised an immensely accurate bomb site and while he is willing to make it available to the Allies, he insists on manufacturing it himself. Soon however, he vanishes and it is left to Homes, assisted by the bumbling Dr. Watson, to decipher a coded message he left behind. Holmes soon realizes that he is up against his old nemesis, Professor Moriarty.